BELLEFONTE, Pa. (AP) - Jerry Sandusky won a court ruling Friday that will let him have an expert testify about a psychiatric condition that his lawyer says helps explain letters he wrote to his accusers and other actions being construed as him grooming victims.

Judge John Cleland granted a motion that sought to put evidence of "histrionic personality disorder" before jurors in Sandusky's child sexual abuse case.

Cleland's order also said the former Penn State assistant football coach must make himself available for prosecutors so they can prepare rebuttal psychiatric testimony.

The defense motion said people with the condition would not necessarily be grooming boys to molest them but instead might be trying to "satisfy the needs of a psyche" with the disorder.

"The jury should not be misled into believing these statements and actions are likely grooming when they are just as likely or more likely histrionic in origin," wrote defense attorney Karl Rominger in the June 11 filing.

Testimony in the 68-year-old former coach's criminal trial is expected to resume Monday. He faces 52 charges he abused 10 boys over 15 years. He has denied the allegations, which led to the ouster of the university president and its longtime coach, Joe Paterno.

Dr. Glen Gabbard, clinical professor of psychiatry at Baylor College of Medicine in Houston, said histrionic personality disorder is overwhelmingly diagnosed in women and could in no way be seen as a reason or explanation for the abuse of children.

"That diagnosis, if he has it, would be completely irrelevant to anything having to do with criminal responsibility for acts of pedophilia," said Gabbard, who is an expert on personality disorders.

"It would make no sense to use this as a defense," said Gabbard, noting he could not diagnose Sandusky. "You are still very much in control of what you do and what you say."

The diagnosis involves someone who suffers highly emotional shifts from one state to another, he said, someone who is overly dramatic, seductive and likes being the center of attention. The classic example, Gabbard said, would be Marilyn Monroe.

"These are people who act like your friend when they just barely met you," he said.